I believe you can sign up for a free trial with LinkedIn Learning. I believe they do have some certifications but it primarily focuses on learning the basics of each product and then more advanced courses. Most employers will want to know that you are familiar with products but wouldn't necessarily require that you be certified in one Microsoft product to be excluded from an HR person. Most MS products are user-friendly and easy to learn once on the job. If LinkedIn Learning no longer offers a free trial, YouTube also offers more than enough videos on the products. If I'm ever a situation where I am trying to learn a task in an MS product for the first time, I normally use YouTube or Linkedin Learning vs. internal IT support.